How to mutually share variables between two python scripts?

Question

I have two scripts, first.py and second.py. I want to send variables of first to second and variables of second to first. But it shows an error. Can any one help me please?

first.py

import second
a=10
print second.b

second.py

import first
b=15
print first.a

The error

AttributeError: 'module' object has no attribute 'b'

• user3012759: what error does it show?
• BallpointBen: This is my guess: when you import second in first.py, the first thing that happens is first is imported to second. Then, first is read, skipping over import second since that's ready happened and Python won't import the same thing twice (otherwise you'd get an infinite loop of imports between the two files). Then the line a=10 is read, and finally print second.b. The issue is that second.py hasn't had time to read down to the bottom because it tried to import first first, and so it hasn't assigned b by the time print second.b is called.

Answer 1

Quite frankly, you don't want to do that. It can lead to circular imports (or partial imports) and lots of confusion. What you normally want is a main program that will import the other two. The main program can then pass data from one to the other since it has access to both.

There is also the idea of Publish / Subscribe - https://en.wikipedia.org/wiki/Publish%E2%80%93subscribe_pattern

In Python you can do this yourself or you can use a convenient package such as PyPubSub or PyDispatcher

Answer 2

You can use a simple memcached server for that. https://pypi.python.org/pypi/python-memcached

• PyManiac: It is usually used for multi-processing needs for simultaneous access but works fine for your case too.

Answer 3

Alternatively, if it is also something that someone else might benefit from, you can try writing it into a third file(Call it variable.txt or something)